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loginrec.c
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loginrec.c
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/*
* Copyright (c) 2000 Andre Lucas. All rights reserved.
* Portions copyright (c) 1998 Todd C. Miller
* Portions copyright (c) 1996 Jason Downs
* Portions copyright (c) 1996 Theo de Raadt
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
** loginrec.c: platform-independent login recording and lastlog retrieval
**/
/* For now lastlog code has been removed as it wasn't being used by Dropbear. */
/*
The new login code explained
============================
This code attempts to provide a common interface to login recording
(utmp and friends) and last login time retrieval.
Its primary means of achieving this is to use 'struct logininfo', a
union of all the useful fields in the various different types of
system login record structures one finds on UNIX variants.
We depend on autoconf to define which recording methods are to be
used, and which fields are contained in the relevant data structures
on the local system. Many C preprocessor symbols affect which code
gets compiled here.
The code is designed to make it easy to modify a particular
recording method, without affecting other methods nor requiring so
many nested conditional compilation blocks as were commonplace in
the old code.
For login recording, we try to use the local system's libraries as
these are clearly most likely to work correctly. For utmp systems
this usually means login() and logout() or setutent() etc., probably
in libutil, along with logwtmp() etc. On these systems, we fall back
to writing the files directly if we have to, though this method
requires very thorough testing so we do not corrupt local auditing
information. These files and their access methods are very system
specific indeed.
For utmpx systems, the corresponding library functions are
setutxent() etc. To the author's knowledge, all utmpx systems have
these library functions and so no direct write is attempted. If such
a system exists and needs support, direct analogues of the [uw]tmp
code should suffice.
Retrieving the time of last login ('lastlog') is in some ways even
more problemmatic than login recording. Some systems provide a
simple table of all users which we seek based on uid and retrieve a
relatively standard structure. Others record the same information in
a directory with a separate file, and others don't record the
information separately at all. For systems in the latter category,
we look backwards in the wtmp or wtmpx file for the last login entry
for our user. Naturally this is slower and on busy systems could
incur a significant performance penalty.
Calling the new code
--------------------
In OpenSSH all login recording and retrieval is performed in
login.c. Here you'll find working examples. Also, in the logintest.c
program there are more examples.
Internal handler calling method
-------------------------------
When a call is made to login_login() or login_logout(), both
routines set a struct logininfo flag defining which action (log in,
or log out) is to be taken. They both then call login_write(), which
calls whichever of the many structure-specific handlers autoconf
selects for the local system.
The handlers themselves handle system data structure specifics. Both
struct utmp and struct utmpx have utility functions (see
construct_utmp*()) to try to make it simpler to add extra systems
that introduce new features to either structure.
While it may seem terribly wasteful to replicate so much similar
code for each method, experience has shown that maintaining code to
write both struct utmp and utmpx in one function, whilst maintaining
support for all systems whether they have library support or not, is
a difficult and time-consuming task.
Lastlog support proceeds similarly. Functions login_get_lastlog()
(and its OpenSSH-tuned friend login_get_lastlog_time()) call
getlast_entry(), which tries one of three methods to find the last
login time. It uses local system lastlog support if it can,
otherwise it tries wtmp or wtmpx before giving up and returning 0,
meaning "tilt".
Maintenance
-----------
In many cases it's possible to tweak autoconf to select the correct
methods for a particular platform, either by improving the detection
code (best), or by presetting DISABLE_<method> or CONF_<method>_FILE
symbols for the platform.
Use logintest to check which symbols are defined before modifying
configure.ac and loginrec.c. (You have to build logintest yourself
with 'make logintest' as it's not built by default.)
Otherwise, patches to the specific method(s) are very helpful!
*/
/**
** TODO:
** homegrown ttyslot()
** test, test, test
**
** Platform status:
** ----------------
**
** Known good:
** Linux (Redhat 6.2, Debian)
** Solaris
** HP-UX 10.20 (gcc only)
** IRIX
** NeXT - M68k/HPPA/Sparc (4.2/3.3)
**
** Testing required: Please send reports!
** NetBSD
** HP-UX 11
** AIX
**
** Platforms with known problems:
** Some variants of Slackware Linux
**
**/
#include "includes.h"
#include "loginrec.h"
#include "dbutil.h"
#include "atomicio.h"
/**
** prototypes for helper functions in this file
**/
#if HAVE_UTMP_H
void set_utmp_time(struct logininfo *li, struct utmp *ut);
void construct_utmp(struct logininfo *li, struct utmp *ut);
#endif
#ifdef HAVE_UTMPX_H
void set_utmpx_time(struct logininfo *li, struct utmpx *ut);
void construct_utmpx(struct logininfo *li, struct utmpx *ut);
#endif
int utmp_write_entry(struct logininfo *li);
int utmpx_write_entry(struct logininfo *li);
int wtmp_write_entry(struct logininfo *li);
int wtmpx_write_entry(struct logininfo *li);
int lastlog_write_entry(struct logininfo *li);
int syslogin_write_entry(struct logininfo *li);
int wtmp_get_entry(struct logininfo *li);
int wtmpx_get_entry(struct logininfo *li);
/* pick the shortest string */
#define MIN_SIZEOF(s1,s2) ( sizeof(s1) < sizeof(s2) ? sizeof(s1) : sizeof(s2) )
/**
** platform-independent login functions
**/
/* login_login(struct logininfo *) -Record a login
*
* Call with a pointer to a struct logininfo initialised with
* login_init_entry() or login_alloc_entry()
*
* Returns:
* >0 if successful
* 0 on failure (will use OpenSSH's logging facilities for diagnostics)
*/
int
login_login (struct logininfo *li)
{
li->type = LTYPE_LOGIN;
return login_write(li);
}
/* login_logout(struct logininfo *) - Record a logout
*
* Call as with login_login()
*
* Returns:
* >0 if successful
* 0 on failure (will use OpenSSH's logging facilities for diagnostics)
*/
int
login_logout(struct logininfo *li)
{
li->type = LTYPE_LOGOUT;
return login_write(li);
}
/* login_alloc_entry(int, char*, char*, char*) - Allocate and initialise
* a logininfo structure
*
* This function creates a new struct logininfo, a data structure
* meant to carry the information required to portably record login info.
*
* Returns a pointer to a newly created struct logininfo. If memory
* allocation fails, the program halts.
*/
struct
logininfo *login_alloc_entry(int pid, const char *username,
const char *hostname, const char *line)
{
struct logininfo *newli;
newli = (struct logininfo *) m_malloc (sizeof(*newli));
(void)login_init_entry(newli, pid, username, hostname, line);
return newli;
}
/* login_free_entry(struct logininfo *) - free struct memory */
void
login_free_entry(struct logininfo *li)
{
m_free(li);
}
/* login_init_entry(struct logininfo *, int, char*, char*, char*)
* - initialise a struct logininfo
*
* Populates a new struct logininfo, a data structure meant to carry
* the information required to portably record login info.
*
* Returns: 1
*/
int
login_init_entry(struct logininfo *li, int pid, const char *username,
const char *hostname, const char *line)
{
struct passwd *pw;
memset(li, 0, sizeof(*li));
li->pid = pid;
/* set the line information */
if (line)
line_fullname(li->line, line, sizeof(li->line));
if (username) {
strlcpy(li->username, username, sizeof(li->username));
pw = getpwnam(li->username);
if (pw == NULL)
dropbear_exit("login_init_entry: Cannot find user \"%s\"",
li->username);
li->uid = pw->pw_uid;
}
if (hostname)
strlcpy(li->hostname, hostname, sizeof(li->hostname));
return 1;
}
/* login_set_current_time(struct logininfo *) - set the current time
*
* Set the current time in a logininfo structure. This function is
* meant to eliminate the need to deal with system dependencies for
* time handling.
*/
void
login_set_current_time(struct logininfo *li)
{
struct timeval tv;
gettimeofday(&tv, NULL);
li->tv_sec = tv.tv_sec;
li->tv_usec = tv.tv_usec;
}
/**
** login_write: Call low-level recording functions based on autoconf
** results
**/
int
login_write (struct logininfo *li)
{
#ifndef HAVE_CYGWIN
if ((int)geteuid() != 0) {
return 1;
}
#endif
/* set the timestamp */
login_set_current_time(li);
#ifdef USE_LOGIN
syslogin_write_entry(li);
#endif
#ifdef USE_LASTLOG
if (li->type == LTYPE_LOGIN) {
lastlog_write_entry(li);
}
#endif
#ifdef USE_UTMP
utmp_write_entry(li);
#endif
#ifdef USE_WTMP
wtmp_write_entry(li);
#endif
#ifdef USE_UTMPX
utmpx_write_entry(li);
#endif
#ifdef USE_WTMPX
wtmpx_write_entry(li);
#endif
return 0;
}
#ifdef LOGIN_NEEDS_UTMPX
int
login_utmp_only(struct logininfo *li)
{
li->type = LTYPE_LOGIN;
login_set_current_time(li);
# ifdef USE_UTMP
utmp_write_entry(li);
# endif
# ifdef USE_WTMP
wtmp_write_entry(li);
# endif
# ifdef USE_UTMPX
utmpx_write_entry(li);
# endif
# ifdef USE_WTMPX
wtmpx_write_entry(li);
# endif
return 0;
}
#endif
/*
* 'line' string utility functions
*
* These functions process the 'line' string into one of three forms:
*
* 1. The full filename (including '/dev')
* 2. The stripped name (excluding '/dev')
* 3. The abbreviated name (e.g. /dev/ttyp00 -> yp00
* /dev/pts/1 -> ts/1 )
*
* Form 3 is used on some systems to identify a .tmp.? entry when
* attempting to remove it. Typically both addition and removal is
* performed by one application - say, sshd - so as long as the choice
* uniquely identifies a terminal it's ok.
*/
/* line_fullname(): add the leading '/dev/' if it doesn't exist make
* sure dst has enough space, if not just copy src (ugh) */
char *
line_fullname(char *dst, const char *src, size_t dstsize)
{
memset(dst, '\0', dstsize);
if ((strncmp(src, "/dev/", 5) == 0) || (dstsize < (strlen(src) + 5))) {
strlcpy(dst, src, dstsize);
} else {
strlcpy(dst, "/dev/", dstsize);
strlcat(dst, src, dstsize);
}
return dst;
}
/* line_stripname(): strip the leading '/dev' if it exists, return dst */
char *
line_stripname(char *dst, const char *src, size_t dstsize)
{
memset(dst, '\0', dstsize);
if (strncmp(src, "/dev/", 5) == 0)
strlcpy(dst, src + 5, dstsize);
else
strlcpy(dst, src, dstsize);
return dst;
}
/* line_abbrevname(): Return the abbreviated (usually four-character)
* form of the line (Just use the last <dstsize> characters of the
* full name.)
*
* NOTE: use strncpy because we do NOT necessarily want zero
* termination */
char *
line_abbrevname(char *dst, const char *src, size_t dstsize)
{
size_t len;
memset(dst, '\0', dstsize);
/* Always skip prefix if present */
if (strncmp(src, "/dev/", 5) == 0)
src += 5;
#ifdef WITH_ABBREV_NO_TTY
if (strncmp(src, "tty", 3) == 0)
src += 3;
#endif
len = strlen(src);
if (len > 0) {
if (((int)len - dstsize) > 0)
src += ((int)len - dstsize);
/* note: _don't_ change this to strlcpy */
strncpy(dst, src, (size_t)dstsize);
}
return dst;
}
/**
** utmp utility functions
**
** These functions manipulate struct utmp, taking system differences
** into account.
**/
#if defined(USE_UTMP) || defined (USE_WTMP) || defined (USE_LOGIN)
/* build the utmp structure */
void
set_utmp_time(struct logininfo *li, struct utmp *ut)
{
# ifdef HAVE_STRUCT_UTMP_UT_TV
ut->ut_tv.tv_sec = li->tv_sec;
ut->ut_tv.tv_usec = li->tv_usec;
# else
# ifdef HAVE_STRUCT_UTMP_UT_TIME
ut->ut_time = li->tv_sec;
# endif
# endif
}
void
construct_utmp(struct logininfo *li,
struct utmp *ut)
{
# ifdef HAVE_ADDR_V6_IN_UTMP
struct sockaddr_in6 *sa6;
# endif
memset(ut, '\0', sizeof(*ut));
/* First fill out fields used for both logins and logouts */
# ifdef HAVE_STRUCT_UTMP_UT_ID
line_abbrevname(ut->ut_id, li->line, sizeof(ut->ut_id));
# endif
# ifdef HAVE_STRUCT_UTMP_UT_TYPE
/* This is done here to keep utmp constants out of struct logininfo */
switch (li->type) {
case LTYPE_LOGIN:
ut->ut_type = USER_PROCESS;
#ifdef _UNICOS
cray_set_tmpdir(ut);
#endif
break;
case LTYPE_LOGOUT:
ut->ut_type = DEAD_PROCESS;
#ifdef _UNICOS
cray_retain_utmp(ut, li->pid);
#endif
break;
}
# endif
set_utmp_time(li, ut);
line_stripname(ut->ut_line, li->line, sizeof(ut->ut_line));
# ifdef HAVE_STRUCT_UTMP_UT_PID
ut->ut_pid = li->pid;
# endif
/* If we're logging out, leave all other fields blank */
if (li->type == LTYPE_LOGOUT)
return;
/*
* These fields are only used when logging in, and are blank
* for logouts.
*/
/* Use strncpy because we don't necessarily want null termination */
strncpy(ut->ut_name, li->username, MIN_SIZEOF(ut->ut_name, li->username));
# ifdef HAVE_STRUCT_UTMP_UT_HOST
strncpy(ut->ut_host, li->hostname, MIN_SIZEOF(ut->ut_host, li->hostname));
# endif
# ifdef HAVE_STRUCT_UTMP_UT_ADDR
/* this is just a 32-bit IP address */
if (li->hostaddr.sa.sa_family == AF_INET)
ut->ut_addr = li->hostaddr.sa_in.sin_addr.s_addr;
# endif
# ifdef HAVE_ADDR_V6_IN_UTMP
/* this is just a 128-bit IPv6 address */
if (li->hostaddr.sa.sa_family == AF_INET6) {
sa6 = ((struct sockaddr_in6 *)&li->hostaddr.sa);
memcpy(ut->ut_addr_v6, sa6->sin6_addr.s6_addr, 16);
if (IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) {
ut->ut_addr_v6[0] = ut->ut_addr_v6[3];
ut->ut_addr_v6[1] = 0;
ut->ut_addr_v6[2] = 0;
ut->ut_addr_v6[3] = 0;
}
}
# endif
}
#endif /* USE_UTMP || USE_WTMP || USE_LOGIN */
/**
** utmpx utility functions
**
** These functions manipulate struct utmpx, accounting for system
** variations.
**/
#if defined(USE_UTMPX) || defined (USE_WTMPX)
/* build the utmpx structure */
void
set_utmpx_time(struct logininfo *li, struct utmpx *utx)
{
# ifdef HAVE_STRUCT_UTMPX_UT_TV
utx->ut_tv.tv_sec = li->tv_sec;
utx->ut_tv.tv_usec = li->tv_usec;
# else /* HAVE_STRUCT_UTMPX_UT_TV */
# ifdef HAVE_STRUCT_UTMPX_UT_TIME
utx->ut_time = li->tv_sec;
# endif /* HAVE_STRUCT_UTMPX_UT_TIME */
# endif /* HAVE_STRUCT_UTMPX_UT_TV */
}
void
construct_utmpx(struct logininfo *li, struct utmpx *utx)
{
# ifdef HAVE_ADDR_V6_IN_UTMP
struct sockaddr_in6 *sa6;
# endif
memset(utx, '\0', sizeof(*utx));
# ifdef HAVE_STRUCT_UTMPX_UT_ID
line_abbrevname(utx->ut_id, li->line, sizeof(utx->ut_id));
# endif
/* this is done here to keep utmp constants out of loginrec.h */
switch (li->type) {
case LTYPE_LOGIN:
utx->ut_type = USER_PROCESS;
break;
case LTYPE_LOGOUT:
utx->ut_type = DEAD_PROCESS;
break;
}
line_stripname(utx->ut_line, li->line, sizeof(utx->ut_line));
set_utmpx_time(li, utx);
utx->ut_pid = li->pid;
/* strncpy(): Don't necessarily want null termination */
strncpy(utx->ut_name, li->username, MIN_SIZEOF(utx->ut_name, li->username));
if (li->type == LTYPE_LOGOUT)
return;
/*
* These fields are only used when logging in, and are blank
* for logouts.
*/
# ifdef HAVE_STRUCT_UTMPX_UT_HOST
strncpy(utx->ut_host, li->hostname, MIN_SIZEOF(utx->ut_host, li->hostname));
# endif
# ifdef HAVE_STRUCT_UTMPX_UT_ADDR
/* this is just a 32-bit IP address */
if (li->hostaddr.sa.sa_family == AF_INET)
utx->ut_addr = li->hostaddr.sa_in.sin_addr.s_addr;
# endif
# ifdef HAVE_ADDR_V6_IN_UTMP
/* this is just a 128-bit IPv6 address */
if (li->hostaddr.sa.sa_family == AF_INET6) {
sa6 = ((struct sockaddr_in6 *)&li->hostaddr.sa);
memcpy(ut->ut_addr_v6, sa6->sin6_addr.s6_addr, 16);
if (IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr)) {
ut->ut_addr_v6[0] = ut->ut_addr_v6[3];
ut->ut_addr_v6[1] = 0;
ut->ut_addr_v6[2] = 0;
ut->ut_addr_v6[3] = 0;
}
}
# endif
# ifdef HAVE_STRUCT_UTMPX_UT_SYSLEN
/* ut_syslen is the length of the utx_host string */
utx->ut_syslen = MIN(strlen(li->hostname), sizeof(utx->ut_host));
# endif
}
#endif /* USE_UTMPX || USE_WTMPX */
/**
** Low-level utmp functions
**/
/* FIXME: (ATL) utmp_write_direct needs testing */
#ifdef USE_UTMP
/* if we can, use pututline() etc. */
# if !defined(DISABLE_PUTUTLINE) && defined(HAVE_SETUTENT) && \
defined(HAVE_PUTUTLINE)
# define UTMP_USE_LIBRARY
# endif
/* write a utmp entry with the system's help (pututline() and pals) */
# ifdef UTMP_USE_LIBRARY
static int
utmp_write_library(struct logininfo *li, struct utmp *ut)
{
setutent();
pututline(ut);
# ifdef HAVE_ENDUTENT
endutent();
# endif
return 1;
}
# else /* UTMP_USE_LIBRARY */
/* write a utmp entry direct to the file */
/* This is a slightly modification of code in OpenBSD's login.c */
static int
utmp_write_direct(struct logininfo *li, struct utmp *ut)
{
struct utmp old_ut;
register int fd;
int tty;
/* FIXME: (ATL) ttyslot() needs local implementation */
#if defined(HAVE_GETTTYENT)
register struct ttyent *ty;
tty=0;
setttyent();
while ((struct ttyent *)0 != (ty = getttyent())) {
tty++;
if (!strncmp(ty->ty_name, ut->ut_line, sizeof(ut->ut_line)))
break;
}
endttyent();
if((struct ttyent *)0 == ty) {
dropbear_log(LOG_WARNING, "utmp_write_entry: tty not found");
return(1);
}
#else /* FIXME */
tty = ttyslot(); /* seems only to work for /dev/ttyp? style names */
#endif /* HAVE_GETTTYENT */
if (tty > 0 && (fd = open(UTMP_FILE, O_RDWR|O_CREAT, 0644)) >= 0) {
(void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET);
/*
* Prevent luser from zero'ing out ut_host.
* If the new ut_line is empty but the old one is not
* and ut_line and ut_name match, preserve the old ut_line.
*/
if (atomicio(read, fd, &old_ut, sizeof(old_ut)) == sizeof(old_ut) &&
(ut->ut_host[0] == '\0') && (old_ut.ut_host[0] != '\0') &&
(strncmp(old_ut.ut_line, ut->ut_line, sizeof(ut->ut_line)) == 0) &&
(strncmp(old_ut.ut_name, ut->ut_name, sizeof(ut->ut_name)) == 0)) {
(void)memcpy(ut->ut_host, old_ut.ut_host, sizeof(ut->ut_host));
}
(void)lseek(fd, (off_t)(tty * sizeof(struct utmp)), SEEK_SET);
if (atomicio(vwrite, fd, ut, sizeof(*ut)) != sizeof(*ut))
dropbear_log(LOG_WARNING, "utmp_write_direct: error writing %s: %s",
UTMP_FILE, strerror(errno));
(void)close(fd);
return 1;
} else {
return 0;
}
}
# endif /* UTMP_USE_LIBRARY */
static int
utmp_perform_login(struct logininfo *li)
{
struct utmp ut;
construct_utmp(li, &ut);
# ifdef UTMP_USE_LIBRARY
if (!utmp_write_library(li, &ut)) {
dropbear_log(LOG_WARNING, "utmp_perform_login: utmp_write_library() failed");
return 0;
}
# else
if (!utmp_write_direct(li, &ut)) {
dropbear_log(LOG_WARNING, "utmp_perform_login: utmp_write_direct() failed");
return 0;
}
# endif
return 1;
}
static int
utmp_perform_logout(struct logininfo *li)
{
struct utmp ut;
construct_utmp(li, &ut);
# ifdef UTMP_USE_LIBRARY
if (!utmp_write_library(li, &ut)) {
dropbear_log(LOG_WARNING, "utmp_perform_logout: utmp_write_library() failed");
return 0;
}
# else
if (!utmp_write_direct(li, &ut)) {
dropbear_log(LOG_WARNING, "utmp_perform_logout: utmp_write_direct() failed");
return 0;
}
# endif
return 1;
}
int
utmp_write_entry(struct logininfo *li)
{
switch(li->type) {
case LTYPE_LOGIN:
return utmp_perform_login(li);
case LTYPE_LOGOUT:
return utmp_perform_logout(li);
default:
dropbear_log(LOG_WARNING, "utmp_write_entry: invalid type field");
return 0;
}
}
#endif /* USE_UTMP */
/**
** Low-level utmpx functions
**/
/* not much point if we don't want utmpx entries */
#ifdef USE_UTMPX
/* if we have the wherewithall, use pututxline etc. */
# if !defined(DISABLE_PUTUTXLINE) && defined(HAVE_SETUTXENT) && \
defined(HAVE_PUTUTXLINE)
# define UTMPX_USE_LIBRARY
# endif
/* write a utmpx entry with the system's help (pututxline() and pals) */
# ifdef UTMPX_USE_LIBRARY
static int
utmpx_write_library(struct logininfo *li, struct utmpx *utx)
{
setutxent();
pututxline(utx);
# ifdef HAVE_ENDUTXENT
endutxent();
# endif
return 1;
}
# else /* UTMPX_USE_LIBRARY */
/* write a utmp entry direct to the file */
static int
utmpx_write_direct(struct logininfo *li, struct utmpx *utx)
{
dropbear_log(LOG_WARNING, "utmpx_write_direct: not implemented!");
return 0;
}
# endif /* UTMPX_USE_LIBRARY */
static int
utmpx_perform_login(struct logininfo *li)
{
struct utmpx utx;
construct_utmpx(li, &utx);
# ifdef UTMPX_USE_LIBRARY
if (!utmpx_write_library(li, &utx)) {
dropbear_log(LOG_WARNING, "utmpx_perform_login: utmp_write_library() failed");
return 0;
}
# else
if (!utmpx_write_direct(li, &ut)) {
dropbear_log(LOG_WARNING, "utmpx_perform_login: utmp_write_direct() failed");
return 0;
}
# endif
return 1;
}
static int
utmpx_perform_logout(struct logininfo *li)
{
struct utmpx utx;
construct_utmpx(li, &utx);
# ifdef HAVE_STRUCT_UTMPX_UT_ID
line_abbrevname(utx.ut_id, li->line, sizeof(utx.ut_id));
# endif
# ifdef HAVE_STRUCT_UTMPX_UT_TYPE
utx.ut_type = DEAD_PROCESS;
# endif
# ifdef UTMPX_USE_LIBRARY
utmpx_write_library(li, &utx);
# else
utmpx_write_direct(li, &utx);
# endif
return 1;
}
int
utmpx_write_entry(struct logininfo *li)
{
switch(li->type) {
case LTYPE_LOGIN:
return utmpx_perform_login(li);
case LTYPE_LOGOUT:
return utmpx_perform_logout(li);
default:
dropbear_log(LOG_WARNING, "utmpx_write_entry: invalid type field");
return 0;
}
}
#endif /* USE_UTMPX */
/**
** Low-level wtmp functions
**/
#ifdef USE_WTMP
/* write a wtmp entry direct to the end of the file */
/* This is a slight modification of code in OpenBSD's logwtmp.c */
static int
wtmp_write(struct logininfo *li, struct utmp *ut)
{
struct stat buf;
int fd, ret = 1;
if ((fd = open(WTMP_FILE, O_WRONLY|O_APPEND, 0)) < 0) {
dropbear_log(LOG_WARNING, "wtmp_write: problem writing %s: %s",
WTMP_FILE, strerror(errno));
return 0;
}
if (fstat(fd, &buf) == 0)
if (atomicio(vwrite, fd, ut, sizeof(*ut)) != sizeof(*ut)) {
ftruncate(fd, buf.st_size);
dropbear_log(LOG_WARNING, "wtmp_write: problem writing %s: %s",
WTMP_FILE, strerror(errno));
ret = 0;
}
(void)close(fd);
return ret;
}
static int
wtmp_perform_login(struct logininfo *li)
{
struct utmp ut;
construct_utmp(li, &ut);
return wtmp_write(li, &ut);
}
static int
wtmp_perform_logout(struct logininfo *li)
{
struct utmp ut;
construct_utmp(li, &ut);
return wtmp_write(li, &ut);
}
int
wtmp_write_entry(struct logininfo *li)
{
switch(li->type) {
case LTYPE_LOGIN:
return wtmp_perform_login(li);
case LTYPE_LOGOUT:
return wtmp_perform_logout(li);
default:
dropbear_log(LOG_WARNING, "wtmp_write_entry: invalid type field");
return 0;
}
}
/* Notes on fetching login data from wtmp/wtmpx
*
* Logouts are usually recorded with (amongst other things) a blank
* username on a given tty line. However, some systems (HP-UX is one)
* leave all fields set, but change the ut_type field to DEAD_PROCESS.
*
* Since we're only looking for logins here, we know that the username
* must be set correctly. On systems that leave it in, we check for
* ut_type==USER_PROCESS (indicating a login.)
*
* Portability: Some systems may set something other than USER_PROCESS
* to indicate a login process. I don't know of any as I write. Also,
* it's possible that some systems may both leave the username in
* place and not have ut_type.
*/
/* return true if this wtmp entry indicates a login */
static int
wtmp_islogin(struct logininfo *li, struct utmp *ut)
{
if (strncmp(li->username, ut->ut_name,
MIN_SIZEOF(li->username, ut->ut_name)) == 0) {
# ifdef HAVE_STRUCT_UTMP_UT_TYPE
if (ut->ut_type & USER_PROCESS)
return 1;
# else
return 1;
# endif
}
return 0;
}
int
wtmp_get_entry(struct logininfo *li)
{
struct stat st;
struct utmp ut;
int fd, found=0;
/* Clear the time entries in our logininfo */
li->tv_sec = li->tv_usec = 0;
if ((fd = open(WTMP_FILE, O_RDONLY)) < 0) {
dropbear_log(LOG_WARNING, "wtmp_get_entry: problem opening %s: %s",
WTMP_FILE, strerror(errno));
return 0;
}
if (fstat(fd, &st) != 0) {
dropbear_log(LOG_WARNING, "wtmp_get_entry: couldn't stat %s: %s",
WTMP_FILE, strerror(errno));
close(fd);
return 0;
}
/* Seek to the start of the last struct utmp */
if (lseek(fd, -(off_t)sizeof(struct utmp), SEEK_END) == -1) {
/* Looks like we've got a fresh wtmp file */
close(fd);